PhD N.A. Gross
Russian Federal Research Center of Physical Culture and Sports (VNIIFK), Moscow

Keywords: children with motor function disorders, foothold, load on foot

Background. Lately the research community has been increasingly concerned with the postural control disorders in children, with a key role played by foot support function classified into the postural control and support response countering sub-functions [1, 2]. Foot arch development backlogs and/or disorders are known to heavily contribute to the growing disorders in the bone and joint structures and ligamentary articulations with the associating foot support, movement coordination and body balancing dysfunctions.

Children with motor disorders are often diagnosed with serious feet deformations which are primarily attributed to the shortage of the age-specific physical activity to further aggravate with the imbalances in the static/ dynamic movement controls [3]. Foot arch loses flexibility and, hence, the shock absorption qualities, strength and muscle tonus with the associating movement limitations. A special priority in this context is given by the research community to the dysfunction correction methods in the disabled children’s rehabilitation systems.

Objective of the study was to rate the foot support functionality disorders in disabled children with motor dysfunctions.

Methods and structure of the study. The foot support function effectiveness was rated using a computerized Pad Professional Test system to obtain the following test data: load distribution on the sole; shift of the body center of mass vertical projection on the sole; vertical-posture pressure on every foot; loads on forefoot and backfoot; effective support square; and the median/ maximal pressure on the sole. The system software gives the means to rate and visualize the vertical-posture foot pressures by color patterns (see Figure 1) and profile variations in the test data arrays for every individual.

Figure 1. Foot support function test profile generated by the computerized Pad Professional Test system

Sampled for the study purposes were children diagnosed with cerebral palsy, autism and some other functionality disorders (n=95).

Study findings and discussion. The cerebral palsy-diagnosed children were tested with compensatory equine (horse foot) due to adaptation to the short-leg-specific walking function deficiencies, with the highest support spots of 15cm² and 14.4cm² on the left and right forefoot making up 57.75% and 56.06% of the total foot support square, respectively. The overload on the forefoot was found to force the heel outside with the associating growth of the forefoot/ heel load ratio typical for the equine/ valgus foot: see the Table hereunder.

Table 1. Foot support profiling test data for the children with motor dysfunctions

The tests diagnosed 22% of the sample with pendulous (loose) foot or equine generally indicative of the complex foot deformations. Some of the children were found to secure the vertical body posture by a single foot support spot with the serious postural control limitations; and 12% of the sample was tested with 100% foot support disability. The autism-diagnosed group was tested with the dominant forefoot support estimated at 10.09cm² (31.36% of the total support) on average. The group with the other diagnoses was tested with the relatively even distribution of the support function, with the left and right foot pressures tested at 31.36% and 28.18% of the totals, respectively.

Foot deformations were found to be passively compensated under pressure albeit the foot often takes a varus/ valgus position. The imbalanced vertical postural control efforts in this case force the trunk and pelvis widely wave in walking in the sagittal, frontal and horizontal planes – that may result in a loss of support and fall on the back [3, 4]. In addition, some children were tested to keep the toe inactive when stepping on the forefoot – that is indicative of the tow extensor dysfunction i.e. failure to stabilize the foot arch with contribution from the sole extensors [4]. Given of Figure 2 hereunder are the equine-valgus foot support profiles with the compensatory forefoot support disorders in children diagnosed with different motor dysfunctions.

Figure 2. Equine-valgus foot support test profiles grouped by the motor dysfunctions

When the foot function is dominated by a backfoot support, the highest pressure in every group was tested on the left foot, with 36% of the sample tested with the heel-only support. The lowest right-foot support (7.18cm² amounting to 71,82% of the total square) was tested in the autism-diagnosed group; with the left-foot support tested at 10.91cm² and the lower square – that is indicative of the poor balance.

The lowest foot support rates (8.9cm² and 32% in the left foot and 8.0cm² and 39% in the right foot) assiciated with the high pressure (52.81kg/cm² and 39.9kg/cm² in the left and right foot, respectively) were tested in the cerebral palsy-diagnosed group, with the test rates indicative of the high stress on the anterior tibial muscle and weakened toe – resulting in the general growht of the limb tonus: see Figures 3-5.

Figure 3. Backfoot load distribution patterns by diagnoses, cm²

Figure 4. Backfoot support square distribution patterns by diagnoses, %

As far as the maximal support pressures are concerned, they were found the least in the other musculoskeletal disorders diagnosed group and the highest in the autism-diagnosed group: see Figure 5.

Figure 5. Maximal support pressures on the forefoot and backfoot by diagnoses, kg/cm²

The autism-diagnosed group was tested with the highest pressure on left foot and the lowest pressure on the right foot, with the lower and higher support squares, respectively.

The cerebral palsy-diagnosed group was tested with the shortest support square and the highest foot pressure – explainable by the serious contracture and shortening of the shin flexors with the pelvis forced backward and the body center of mass vertical projection point moved back from the support spot. To correct the body center of mass projection point, the child has to shift the shoulder girdle and head forward to balance on the effective foot support spot – being unable to use the whole foot, and this is the reason for the high pressure on the relatively little support spot [4, 5] .

The group diagnosed with equine/ varus foot with dominating heel support was tested with 8.5cm² and 9.5cm² left and right foot support squares, respectively, with the forefoot support sport making up 2.3-3.2cm² only and, as a result, the group was diagnosed with the joint subluxations [2]: see Figure 6.

Figure 6. Foot pressure profiles for the group diagnosed with equine/ varus foot

Given on Figure 7 is the range of additional test data generated by the computerized Pad Professional Test system for one child in the sample.

Figure 7. Individual effective foot support profiling test data for one of the subjects, generated by the computerized Pad Professional Test system

The above individual effective foot support profile showed the foot placement disorder due to the sole flexion (equine or horse foot) as a result of pareses of shin extensors. The foot support dysfunction includes the heel disability due to the long-lasting physical inactivity and the small tibia muscle dysfunction with its front section flattened by the overload [5, 6]. The heel was found forced upward with the calcaneal tendon overstressed and the natural heelball-toe roll heavily complicated.

Conclusion. The study data and analyses showed the cerebral palsy diagnosed group lagging behind the others in the effective sole square with the foot pressure being relatively high. The growing effective sole square in this group was found associated with the growing pressure on the internal edge of the sole under the metatarsus bone; with 30% of the sample diagnosed with flat deformations in the feet. The study found a non-linear correlation between the loads on the forefoot and heel that may be attributed to paresis/ paralysis of the foot extensor muscles or compensatory equines (horse foot) i.e. adaptation to the short-leg-specific walking deficiencies. Some children were tested to keep the toe unloaded when stepping on the forefoot.

The autism-diagnosed group was tested with an expressed asymmetry of the foot support function with the right foot overloading indicative of the postural control imbalances. The other study groups were tested with the evenly distributed loads on the both feet indicative of the relatively fair support function.

References

1. Vasilyeva L.F. Vizualnaya diagnostika narusheniy statiki i dinamiki oporno-dvigatelnogo apparata cheloveka [Visual diagnostics of static and dynamic disturbances in human musculoskeletal system]. Ivanovo: MIK publ., 1996, 110 p.
2. Gross D., Fetto D., Rouzen E. Funktsionalnoe issledovanie kostno-myshechnoy sistemy [Functional study of musculoskeletal system]. Moscow: BIKOM, 2011, 458 p.
3. Kashuba V.A. Biomekhanika osanki [Posture biomechanics]. Kiev: Olimpiyskaya literatura publ., 2005, 279 p.
4. Lif D. Stopa i golenostopny sustav [Foot and ankle joint]. Transl. from Engl. Podiatr publ., 2012, 104 p.
5. Perkhurova I.S., Luzinovich V.M., Sologubov E.G. Regulyatsiya pozy i khodby pri detskom tserebralnom paraliche i nekotorye sposoby korrektsii [Regulation of posture and walk under infantile cerebral palsy and some correction methods]. Moscow: Knizhnaya palata publ., 1996, 248 p.
6. Smirnov G.V. Kompleksnaya otsenka ustoychivosti vertikalnoy pozy cheloveka v norme i pri patologii tazobedrennogo sustava [Comprehensive assessment of stability of vertical posture in man in health and disease of hip joint]. PhD diss. abstract. Moscow, 1994.

Corresponding author: info@vniifk.ru

Abstract

Since the load on feet is the highest in vertical posture, foot developmental trainings are critical for the handicapped children’s postural control skills in any motor situation. Sampled for the study purposes were the children diagnosed with cerebral palsy, autism and some other functionality disorders (n=95). The foot function was rated using a computerized Pad Professional Test system to obtain the following test data: load distribution on the sole; shift of the body center of mass vertical projection on the sole; load on every foot in vertical posture; load on the front and back parts of the foot; effective sole square; and the median/ maximal pressure on the sole.

The study data and analyses showed the cerebral palsy diagnosed group lagging behind the others in the effective sole square with the foot pressure being relatively high. The growing effective sole square in this group was found associated with the growing pressure on the internal edge of the sole under the metatarsus bone; with 30% of the sample diagnosed with flat deformations in the feet. The study found a non-linear correlation between the loads on the forefoot and heel that may be attributed to paresis/ paralysis of the foot extensor muscles or compensatory equines (horse foot) i.e. adaptation to the short-leg-specific walking deficiencies. Some children were tested to keep the toe unloaded when stepping on the forefoot.

The autism-diagnosed group was tested with an expressed asymmetry of the foot support function with the right foot overloading indicative of the postural control imbalances. The other study groups were tested with the evenly distributed loads on the both feet indicative of the relatively fair support function.